Simultaneously Enhancing Efficiency and Lifetime of Ultralong Organic Phosphorescence Materials by Molecular Self-Assembly

Article abstract of DOI:10.1021/jacs.8b03867

Metal-free organic phosphorescence materials are of imperious demands in optoelectronics and bioelectronics. However, it is still a formidable challenge to develop a material with simultaneous efficiency and lifetime enhancement under ambient conditions. In this study, we design and synthesize a new class of high efficient ultralong organic phosphorescence (UOP) materials through self-assembly of melamine and aromatic acids in aqueous media. A supramolecular framework can be formed via multiple intermolecular interactions, building a rigid environment to lock the molecules firmly in a three-dimensional network, which not only effectively limits the nonradiative decay of the triplet excitons but also promotes the intersystem crossing. Thus, the supermolecules we designed synchronously achieve an ultralong emission lifetime of up to 1.91 s and a high phosphorescence quantum efficiency of 24.3% under ambient conditions. To the best of our knowledge, this is the best performance of UOP materials with simultaneous efficiency and lifetime enhancement. Furthermore, it is successfully applied in a barcode identification in darkness. This result not only paves the way toward high efficient UOP materials but also expands their applications.

Full text of DOI:10.1021/jacs.8b03867

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Article
Simultaneously Enhancing Efficiency and Lifetime of Ultralong
Organic Phosphorescence Materials by Molecular Self-assembly
Lifang Bian, Huifang Shi, Xuan Wang, Kun Ling, Huili Ma, Mengping Li, Zhichao Cheng,
Chaoqun Ma, Suzhi Cai, Qi Wu, Nan Gan, Xiangfei Xu, Zhongfu An, and Wei Huang
J. Am. Chem. Soc., Just Accepted Manuscript • DOI: 10.1021/jacs.8b03867 • Publication Date (Web): 05 Aug 2018
Downloaded from http://pubs.acs.org on August 5, 2018
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Simultaneously Enhancing Efficiency and Lifetime of Ultra-
long Organic Phosphorescence Materials by Molecular Self-
assembly
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┴
Lifang Bian†, , Huifang Shi†, ┴, Xuan Wang†, Kun Ling†, Huili Ma†, Mengping Li†, Zhichao Cheng†,
Chaoqun Ma†, Suzhi Cai†, Qi Wu†, Nan Gan†, Xiangfei Xu†, Zhongfu An*,†, Wei Huang*,†, ‡
†Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Jiangsu National Synergistic
Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanꢀ
jing 211800, P.R. China.
‡
Shanxi Institute of Flexible Electronics (SIFE), Northwestern Polytechnical University (NPU), 127 West Youyi Road,
Xi'an 710072, China.
ABSTRACT: Metalꢀfree organic phosphorescence materials are of imperious demands in optoelectronics and bioelectronics.
However, it is still a formidable challenge to develop a material with simultaneous efficiency and lifetime enhancement under amꢀ
bient conditions. In this study, we design and synthesize a new class of high efficient ultralong organic phosphorescence (UOP)
materials through selfꢀassembly of melamine and aromatic acids in aqueous media. A supramolecular framework can be formed via
multiple intermolecular interactions, building a rigid environment to lock the molecules firmly in a threeꢀdimensional network,
which not only effectively limits the nonꢀradiative decay of the triplet excitons, but also promotes the intersystem crossing. Thus,
the supermolecules we designed synchronously achieve an ultralong emission lifetime of up to 1.91 s and a high phosphorescence
quantum efficiency of 24.3% under ambient conditions. To the best of our knowledge, this is the best performance of UOP materiꢀ
als with simultaneous efficiency and lifetime enhancement. Furthermore, it is successfully applied in a barcode identification in
darkness. This result not only paves the way toward high efficient UOP materials, but also expands their applications.
INTRODUCTION
doping method,36ꢀ39 the construction of metalꢀorganic frameꢀ
works (MOFs)40 or ionic crystals,41 and so on,42ꢀ47 which
Organic phosphorescence, which originates from the radiaꢀ
tive transition of triplet excitons, has aroused an increasing
attention in optoelectronic1ꢀ2 and biological3ꢀ6 areas because of
their long emission lifetimes, high quantum yields, and large
Stokes shifts.7ꢀ9 So far, most of the room temperature phosphoꢀ
rescence is limited to inorganic compounds or organometallic
complexes, such as Ir (III), Pt (II) and Ru (III) complexes,10ꢀ13
because the metalꢀinduced spin orbit coupling (SOC) can
promote the intersystem crossing (ISC) for phosphorescence
enhancement. Considering the high cost and limited resources
of noble metals, more and more efforts have been devoted on
metalꢀfree organic phosphorescence recently.14ꢀ23 However,
exploring metalꢀfree organic phosphorescence compounds
with ultralong lifetime is extremely difficult due to the ineffiꢀ
cient ISC caused by weak spin orbit coupling, rapid nonꢀ
radiative decay rate of the triplet excitons and some unpredictꢀ
able quenching factors from the surroundings such as
oxygen.24ꢀ25 Therefore, researchers usually take two ways to
obtain efficient phosphorescence. One is boosting spin orbit
coupling by the introduction of aromatic carbonyls, hetero
atoms and heavy atoms to achieve highly efficient phosphoꢀ
rescence. 26ꢀ32 The other is suppressing the nonꢀradiative transiꢀ
tion of triplet excitons by crystal engineering,33ꢀ35 hostꢀguest
Figure 1. Schematic representation of design concept and supraꢀ
molecular architecture.
embed phosphors into a solid matrix, making them be isolated
from oxygen and structurally fixed to limit nonꢀradiative deꢀ
cay, and thus the longꢀlived room temperature phosphoresꢀ
cence is realized. Recently, our group has reported UOP with
an emission lifetime as long as 1.35 seconds through Hꢀ
aggregated molecules stabilizing the triplet excitons under
ambient conditions.48 Up to now, the researchers mainly focus
on improving efficiency or lifetime of organic phosphoresꢀ
cence (Figure S1). Owing to weak spin orbit coupling and the
rapid rate of nonꢀradiative decay in metalꢀfree organics, deꢀ
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veloping organic phosphorescent materials with both high
Page 2 of 7
system, rigid molecular environment can be constructed, thus
suppressing nonꢀradiative transition for phosphorescence enꢀ
hancement. With this in mind, we designed and synthesized a
new supramolecular framework (MAꢀIPA) with ultralong orꢀ
ganic phosphorescence through selfꢀassembly of melamine
(MA) and aromatic acids in aqueous media (Figure 1). Impresꢀ
sively, MAꢀIPA supramolecular material showed an ultralong
lifetime of 1.91 s and a high phosphorescent efficiency of up
to 24.3%, which is a record result among reported organic
materials so far. Given the unique ultralong phosphorescence,
this type of supramolecular material was successfully applied
in a barcode identification in darkness. This study will provide
a simple and green method to achieve a unique supramolecular
UOP system with simultaneously a high quantum efficiency
and an ultralong lifetime.
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efficiency and ultralong lifetime is still a formidable chalꢀ
lenge.49
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RESULTS AND DISCUSSION
Synthesis. The supramolecular framework of MAꢀIPA was
synthesized from the mixture of MA and isophthalic acid
o
(IPA) in aqueous solution at 150 C. During gradient cooling,
Figure 2. Photophysical properties of MAꢀIPA supermolecule
framework under ambient conditions. a) The fluorescence microꢀ
scope images with the excitation on and off. b) Steadyꢀstate phoꢀ
toluminescence (PL, blue dashed line) and phosphorescence (red
solid line) spectra under 300 nm excitation. c) Excitationꢀ
phosphorescence mapping. d) Timeꢀresolved phosphorescence
decay and fitting curves (black line) of the emission bands at 466
and 488 nm, respectively.
a large amounts of colorless needle crystals (Figure 2a) were
obtained with a high yield of 86%. The chemical structure of
MAꢀIPA was thoroughly characterized by Xꢀray diffraction
and elemental analysis. The phase purity of the crystals was
further verified by powder Xꢀray diffraction shown in Figure
S2.
Photophysical Properties of MA-IPA. The photophysical
properties of MAꢀIPA in crystal state were firstly investigated
under ambient conditions. Under irradiation by UVꢀlight, the
needleꢀlike crystals took on blue emission. Interestingly, after
turning off the UVꢀlight source, the sample showed bright
bluish green afterglow, which lasted for nearly 20 s by naked
Supramolecular chemistry has played an important role in
chemistry and material science since the 1960s, which offers
an attractive approach to prepare wellꢀorganized functional
materials by selfꢀassembly of molecular subunits or compoꢀ
nents.50ꢀ51 With the intermolecular locking by multiple nonꢀ
covalent forces including Hꢀbonding, π−π stacking, van der
Waals force, electrostatic interaction, etc. in selfꢀassembly
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Figure 3. Single crystal structure of MAꢀIPA. Molecular packing along the a) aꢀaxis and b) cꢀaxis. Intermolecular interactions from the
same plane with c) MA as the centre and d) with IPA as the centre. Intermolecular interactions of e) MA and f) IPA with adjacent planes,
respectively.
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eyes. As shown in Figure 2b, the steadyꢀstate photoluminesꢀ
cence spectrum showed a blue emission band at around 356
nm and a green emission band with peaks at 466 and 488 nm,
which was different from MA with a blue emission at 460 nm
and IPA with three emission peaks at approximately 390, 480
and 505 nm (Figure S3). And the strongest emission band at
approximately 488 nm (Figure 2c). From the lifetime decay
profiles, it was confirmed that the blue emission was assigned
to the fluorescence (Figure S4a). The green emission was due
to the phosphorescence with ultralong emission lifetimes of
1.91 s and 1.85 s under ambient conditions (Figure 2d), which
is 5.1 and 1.4 times more than MA crystal with a lifetime of
0.37 s and IPA crystal with a lifetime of 1.36 s, respectively
(Figure S5). The phosphorescence nature of ultralong emission
was further confirmed by its sensitivity to oxygen (Figure S7).
Surprisingly, the absolute phosphorescence quantum efficienꢀ
cy of MAꢀIPA crystals reached as high as 24.3%. To the best
of our knowledge, it is the best ultralong organic phosphoresꢀ
cent material with both ultralong lifetime and high phosphoꢀ
rescence efficiency (Figure S1). Additionally, with temperaꢀ
cules, which are linked by multiple short and intense hydrogen
bonds and Van der Waals' forces, forming a latticeꢀlike strucꢀ
ture. Notably, the intermolecular nonꢀcovalent interactions
lead the molecules to assemble in a highly ordered supramoꢀ
lecular network. Four molecules of water can be captured by
hydrogen bonding in a network, and a pair of water dimer with
hydrogen bonding links amino groups on MA to form a hexaꢀ
gon by hydrogen bonds (Figure 3a). Moreover, these water
molecules are linked to the upper and lower molecules respecꢀ
tively by various hydrogen bonds (Figure 3b), which makes
great contributions to hinder molecular motions for suppressꢀ
ing nonꢀradiative transition of triplet excitons and promoting
ultralong phosphorescence at room temperature.
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To gain deeper insight into the influence of water molecules
on UOP emission, we conducted a set of control experiments
after dehydration by heating. After MAꢀIPA crystal underwent
o
thermal treatment at 150 C for 2 h, both the lifetime and
quantum efficiency of phosphorescence decreased dramaticalꢀ
ly into 1.21 s and 4.37% (Figure S10 and Table S1 and S2),
indicating the water played a vital role for UOP enhancement.
From powder XRD (PXRD) analysis in Figure S2a, it is worth
noting that the PXRD pattern has significant changes after
MAꢀIPA crystal was dehydrated by heating. Therefore, we
speculated that after thermal treatment, multiple hydrogen
bonds in MAꢀIPA crystal might be destroyed to get a loose
structure to accelerate nonꢀradiative transitions and thus
quenched phosphorescence.
o
ture increasing from 30 to 140 C, the phosphorescence intenꢀ
sity of MAꢀIPA gradually decreased. When the temperature
o
was raised to 115 C, the phosphorescence signals almost disꢀ
appeared (Figure S8).
Mechanism Analysis for High Efficient UOP Emission.
To gain insights into the mechanism of the unique UOP for
this supramolecular architecture, the molecular structure and
intermolecular interactions in MAꢀIPA crystal were investiꢀ
gated by Xꢀray single crystal diffraction, as shown in Figure 3.
In this centrosymmetric unit of MAꢀIPA crystal, IPA molecule
loses a proton and becomes negative charged IPAꢀ, while a
nitrogen atom of triazine in MA molecule is protonated as
cationic MAH+. Thus, the supermolecule of MAꢀIPA includes
three parts, an MA cation, an IPA anion and two water moleꢀ
Specifically, taking an MA cation as a core, there exist mulꢀ
tiple intermolecular interactions within the same plane and
between the upper and lower layers, including NꢀH···O,
N···HꢀO, NꢀH···N, C···HꢀO, etc. (Figure 3c and 3e). Taking
an IPA anion as a core, apart from some common bonds
above,
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Figure 4. Photophysical properties and single crystal structure of MAꢀTPA in solid state under ambient conditions. a) The fluorescence
microscope images (left) and photographs (right) of MAꢀTPA crystals before and after irradiation with a handꢀheld 310 nm UV lamp. b)
Normalized photoluminescence (PL, blue line) and ultralong phosphorescence (red line) spectra of MAꢀTPA under 310 nm excitation. c)
Transient photoluminescence decay mapping of MAꢀTPA crystals. The color changed from red to blue indicates the decrease in emission
intensity. d) Intermolecular interactions viewed along the c axis. e) Intermolecular stacking viewed along the b axis.
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there also exist many multiple intermolecular interactions
within the same plane and between the upper and lower layers,
such as OꢀH···O, OꢀH···HꢀO, CꢀH···Hꢀπ, etc. (Figure 3d and
3f). The detailed hydrogen bond types and bond lengths are
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Figure 5. Application of ultralong phosphors. The UOP material
was printed on a piece of filter paper to form a twoꢀdimensional
code painting. a) Twoꢀdimensional code painting of our institute.
The gray part is covered with MAꢀIPA material. Photographs
showed in Table S3. These intermolecular interactions in this
taken b) under 365 nm lamp and c) after removal of 365 nm UV
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supramolecular network play important roles in restricting the
lamp.
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molecular motions to reduce the nonꢀradiative transition for
approximately 345, 415, 482 and 509 nm, respectively (Figure
4b). Timeꢀresolved emission spectrum (TRES) revealed a reꢀ
markable luminescence lifetime of MAꢀTPA crystals (Figure
4c). Critically, the crystalline sample gave rise to the longest
lifetime (1.09 s) when irradiated at around 310 nm. In order to
investigate the origin of the enhanced UOP lifetime, its single
crystal structure was analyzed. Similarly, MAꢀTPA is also
arranged in a highly ordered structure through hydrogen bondꢀ
ing selfꢀassembly. In this process, MA gets a proton to become
a cation MAH+, which is connected with adjacent molecules
through a large amounts of intermolecular forces (hydrogen
bonding and Van der Waals' forces), such as NꢀH···N, Nꢀ
H···π, NꢀH···O, etc. (Figure 4d and 4e). Meanwhile, two proꢀ
tons in TPA are lost, forming TPA2ꢀ, which forms a very
symmetrical topological structure with adjacent four MA and
two water molecules by intermolecular forces, including Cꢀ
H···O, CꢀH···HꢀO, CꢀH···N and so on (Figure S7). The deꢀ
tailed hydrogen bond types and bond lengths are summarized
in Table S5. As a result, molecular motions in the supramolecꢀ
ular architecture were effectively limited so that the ultralong
phosphorescence was achieved. Similarly, the theoretical simꢀ
ulations were carried out to verify our concept (Figure S13).
After selfꢀassembly, the SOC ξ (S1, Tn) of MAꢀTPA increased
largely from 1.89 (TPA monomer) to 16.1 cmꢀ1, facilitating
ISC process for phosphorescence generation. As we expected,
MAꢀPA also showed blue ultralong phosphorescence with a
lifetime of 0.68 s and a quantum yield of 0.82% (Figure S16
and Table S1 and S2) after stoppage of excitation, surpassing
the corresponding monomers but below MAꢀIPA and MAꢀ
TPA. From its single crystal analysis, it was found that there
was no water molecule in crystal (Figure S15), which was
different from MAꢀIPA and MAꢀTPA crystals. Additionally,
no hydrogen bonding was observed between PA molecules, to
some extent, possibly accelerating nonꢀradiative transitions to
weaken UOP compared with MAꢀIPA and MAꢀTPA crystals
(Table S4).
ultralong phosphorescence.
Furthermore, the theoretical calculations via firstꢀprinciple
timeꢀdependent density functional theory (TDꢀDFT) were
conducted on single molecule and selfꢀassembly structures in
both singlet and triplet excited states. From the calculated reꢀ
sults shown in Figure S11, the energy gaps between the singlet
and triplet states for both IPA monomer and MAꢀIPA dimer
containing one water molecule were small, which will faciliꢀ
tate ISC process. After selfꢀassembly of MA, IPA and water,
the SOC ξ (S1, Tn) increased largely from 19.4 (IPA monomer)
to 33.9 cmꢀ1. That is to say, in the process of selfꢀassembly,
hydrogen bonds locked the monomers firmly to promote the
ISC from singlet to triplet states, and then leading to high effiꢀ
cient phosphorescence, which was further confirmed by a fastꢀ
er ISC rate (9.3 × 107 sꢀ1) for MAꢀIPA supramolecular frameꢀ
work than those for MA (1.7 × 106 sꢀ1) and IPA (8.7 × 106 sꢀ1)
(Table S4). Furthermore, it was found that MAꢀIPA supramoꢀ
lecular framework showed faster radiative transition (0.13 sꢀ1)
and slower nonradiative decay rates (0.40 sꢀ1) compared with
monomers (Table S4), which were contributed to prolonging
emission lifetime of MAꢀIPA supramolecular framework.
Taken these results together, we reasoned that high efficient
UOP was ascribed to suppressing nonꢀradiative transition and
populating triplet excitons through supramolecular selfꢀ
assembly.
To view the universality of this new material system with
remarkable UOP feature under ambient conditions, we deꢀ
signed expanded experiments that MA assembled with terephꢀ
thalic acid (TPA) and phthalic acid (PA) into supramolecular
frameworks of MAꢀTPA and MAꢀPA, respectively. The UOP
lifetime of MAꢀTPA was prolonged to 1.09 s and the phosphoꢀ
rescence quantum efficiency reached 19.4%. Like MAꢀIPA,
both lifetime and efficiency of UOP in MAꢀTPA crystal also
improved substantially compared with building monomers
(Figure S5). For MAꢀTPA crystals, the bulk morphology in
microꢀnanoscale was observed by fluorescence microscope, as
shown in Figure 4a. Under irradiation by a 310 nm illuminant,
the sample took on skyꢀblue emission. After turning off the
UV lamp, the sample presented a bluish green UOP, lasting
for several seconds. And the PL emission located at
Application in barcode identification. Given the high effiꢀ
cient UOP feature of the supramolecular framework, a 2ꢀ
dimenstional barcode of our institute’s (Institute of Advanced
Materials @ Nanjing Tech University) WeChat identification
pattern was fabricated using the phosphors of MAꢀIPA. As
illustrated in Figure 5, the pattern was painted with MAꢀIPA
on a piece of filter paper by screenꢀprinting. The gray part of
the pattern was the ground MAꢀIPA material (Figure 5a). Unꢀ
der UVꢀlamp excitation, it showed bluish violet luminescence
in a dark room, which cannot be recognized by the WeChat
scanning (Figure 5b). When the UV lamp was switched off,
however, MAꢀIPA emitted luminous blueꢀgreen ultralong
phosphorescence (Figure 5c), which can be identified immediꢀ
ately by scanning the barcode and the identified information
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(6) Zhao, Q.; Huang, C.; Li, F., Chem. Soc. Rev. 2011, 40, 2508ꢀ
2524.
(7) Baldo, M.; Thompson, M.; Forrest, S., Nature. 2000, 403, 750ꢀ
753.
was showed in Figure S17. Thus, we realized a barcode identiꢀ
fication by this UOP supramolecular material in the darkness.
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2
3
4
5
6
7
8
9
(8) Baldo, M. A.; O'brien, D.; You, Y.; Shoustikov, A.; Sibley, S.;
Thompson, M.; Forrest, S., Nature. 1998, 395, 151ꢀ154.
(9) Xu, S.; Chen, R.; Zheng, C.; Huang, W., Adv. Mater. 2016, 28,
9920ꢀ9940.
(10) Evans, R. C.; Douglas, P.; Winscom, C. J., Coord. Chem. Rev.
2006, 250, 2093ꢀ2126.
(11) Au, V. K.ꢀM.; Wong, K. M.ꢀC.; Tsang, D. P.ꢀK.; Chan, M.ꢀY.;
Zhu, N.; Yam, V. WꢀW. J, J. Am. Chem. Soc. 2010, 132, 14273ꢀ
14278.
(12) Whittemore, T. J.; White, T. A.; Turro, C., J. Am. Chem. Soc.
2018, 140, 229ꢀ234.
(13) You, Y.; Lee, S.; Kim, T.; Ohkubo, K.; Chae, W. S.; Fukuzumi,
S.; Jhon, G. J.; Nam, W.; Lippard, S. J., J. Am. Chem. Soc. 2011, 133,
18328ꢀ18342.
(14) Cai, S.; Shi, H.; Li, J.; Gu, L.; Ni, Y.; Cheng, Z.; Wang, S.;
Xiong, W.; Li, L.; An, Z.; Huang, W., Adv. Mater. 2017, 29,
1701244ꢀ1701249.
(15) Cai, S.; Shi, H.; Tian, D.; Ma, H.; Cheng, Z.; Wu, Q.; Gu, M.;
Huang, L.; An, Z.; Peng, Q.; Huang, W., Adv. Funct. Mater. 2018, 28,
1705045ꢀ1705051.
(16) Hirata, S., Adv. Opt. Mater. 2017, 5, 1700116ꢀ1700165.
(17) Baroncini, M.; Bergamini, G.; Ceroni, P., Chem. Commun.
2017, 53, 2081ꢀ2093.
(18) Wu, H.; Zhou, Y.; Yin, L.; Hang, C.; Li, X.; Agren, H.; Yi, T.;
Zhang, Q.; Zhu, L., J. Am. Chem. Soc. 2017, 139, 785ꢀ791.
(19) Yu, L.; Wu, Z.; Zhong, C.; Xie, G.; Zhu, Z.; Ma, D.; Yang, C.,
Adv. Opt. Mater. 2017, 5, 1700588ꢀ1700595.
(20) Yu, Z.; Wu, Y.; Xiao, L.; Chen, J.; Liao, Q.; Yao, J.; Fu, H., J.
Am. Chem. Soc. 2017, 139, 6376ꢀ6381.
(21) Gu, L.; Shi, H.; Gu, M.; Ling, K.; Ma, H.; Cai, S.; Song, L.; M
a, C.; Li, H.; Xing, G.; Hang, X.; Li, J.; Gao, Y.; Yao, W.; Shuai, Z.;
An, Z.; Liu, X.; Huang, W., Angew. Chem. Int. Ed. 2018, 57, 5425ꢀ
8431.
(22) Jiang, K.; Wang, Y.; Cai, C.; Lin, H., Adv. Mater. 2018,
1800783ꢀ1800790.
(23) Lucenti, E.; Forni, A.; Botta, C.; Carlucci, L.; Giannini, C.;
Marinotto, D.; Pavanello, A.; Previtali, A.; Righetto, S.; Cariati, E.,
Angew. Chem. Int. Ed. 2017, 56, 16302ꢀ16307.
(24) Schulman, E. M.; Parker, R. T., J. Phys. Chem. 1977, 81, 1932ꢀ
1939.
(25) Gu, L.; Shi, H.; Miao, C.; Wu, Q.; Cheng, Z.; Cai, S.; Gu, M.;
Ma, C.; Yao, W.; Gao, Y.; An, Z.; Huang, W., J. Mater. Chem. C.
2018, 6, 226ꢀ233.
(26) Bolton, O.; Lee, K.; Kim, H. J.; Lin, K. Y.; Kim, J., Nat. Chem.
2011, 3, 205ꢀ210.
(27) Ma, H.; Shi, W.; Ren, J.; Li, W.; Peng, Q.; Shuai, Z., J. Phys.
Chem. Lett. 2016, 7, 2893ꢀ2898.
CONCLUSIONS
In summary, a new class of supramolecular frameworks
with high efficiency ultralong organic phosphorescence were
synthesized by selfꢀassembly of melamine and aromatic acids
in aqueous media. With multiple intermolecular interactions,
the supramolecular frameworks showed threeꢀdimensional
networks, which not only effectively limited the nonꢀradiative
decay of the triplet excitons, but also promoted the intersystem
crossing. Impressively, a record performance of UOP with
both an ultralong emission lifetime of up to 1.91 s and a high
phosphorescence quantum efficiency of 24.3% was demonꢀ
strated under ambient conditions. Taking advantage of its high
efficient UOP, MAꢀIPA was successfully utilized in a barcode
identification in a dark environment. This study not only proꢀ
vides an innovative and universal approach to achieving highꢀ
ly efficient UOP materials, but also expands the potential apꢀ
plication of ultralong organic phosphorescence.
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ASSOCIATED CONTENT
Supporting Information.
Scheme S1, chemical structures in this work, Figure S1ꢀ17 and
Table S1ꢀ6, displaying phosphorescence lifetime and efficiency
chart of organic materials, PXRD patterns, emission spectra, lifeꢀ
time decay profiles, detail crystal date, the TDꢀDFT calculations
and energy levels, the additional measurement supporting applicaꢀ
tions. SV1ꢀ2, complementary videos. This material is available
free of charge via the Internet at http://pubs.acs.org.
AUTHOR INFORMATION
Corresponding Author
iamwhuang@njtech.edu.cn (W. Huang);
iamzfan@njtech.edu.cn (Z. An).
Author Contributions
┴These authors contributed equally.
ACKNOWLEDGMENT
This work is supported by the National Natural Science Foundaꢀ
tion of China (51673095 and 61505078), National Basic Research
Program of China (973 Program, No. 2015CB932200), the Natuꢀ
ral Science Foundation (BK20150962), Natural Science Fund for
Colleges and Universities (17KJB430020) and "HighꢀLevel Talꢀ
ents in Six Industries"(XCLꢀ025) of Jiangsu Province and Nanꢀ
jingTech Startꢀup Grant (3983500158 and 3983500169). Meanꢀ
while, we are grateful to the High Performance Computing Center
of Nanjing Tech University for supporting the computational
resources.
(28) Sun, C.; Ran, X.; Wang, X.; Cheng, Z.; Wu, Q.; Cai, S.; Gu, L.;
Gan, N.; Shi, H.; An, Z.; Shi, H.; Huang, W., J. Phys. Chem. Lett.
2018, 9, 335ꢀ339.
(29) Gong, Y.; Chen, G.; Peng, Q.; Yuan, W. Z.; Xie, Y.; Li, S.;
Zhang, Y.; Tang, B. Z., Adv. Mater. 2015, 27, 6195ꢀ6201.
(30) Shoji, Y.; Ikabata, Y.; Wang, Q.; Nemoto, D.; Sakamoto, A.;
Tanaka, N.; Seino, J.; Nakai, H.; Fukushima, T., J. Am. Chem. Soc.
2017, 139, 2728ꢀ2733.
REFERENCES
(1) Reineke, S., Nat. Photon. 2014, 8, 269ꢀ270.
(2) Xu, H.; Chen, R.; Sun, Q.; Lai, W.; Su, Q.; Huang, W.; Liu, X.,
Chem. Soc. Rev. 2014, 43, 3259ꢀ3302.
(3) Cui, Y.; Xu, H.; Yue, Y.; Guo, Z.; Yu, J.; Chen, Z.; Gao, J.;
Yang, Y.; Qian, G.; Chen, B., J. Am. Chem. Soc. 2012, 134, 3979ꢀ
3982.
(4) Yang, Y.; Zhao, Q.; Feng, W.; Li, F., Chem. Rev. 2012, 113,
192ꢀ270.
(31) Xie, Y.; Ge, Y.; Peng, Q.; Li, C.; Li, Q.; Li, Z., Adv. Mater.
2017, 29, 1606829ꢀ1606835.
(32) Yang, Z.; Mao, Z.; Zhang, X.; Ou, D.; Mu, Y.; Zhang, Y.;
Zhao, C.; Liu, S.; Chi, Z.; Xu, J.; Wu, Y. C.; Lu, P. Y.; Lien, A.;
Bryce, M. R., Angew. Chem. Int. Ed. 2016, 55, 2181ꢀ2185.
(33) Mao, Z.; Yang, Z.; Mu, Y.; Zhang, Y.; Wang, Y. F.; Chi, Z.;
Lo, C. C.; Liu, S.; Lien, A.; Xu, J., Angew. Chem. Int. Ed. 2015, 54,
6270ꢀ6273.
(34) Yuan, W.; Shen, X.; Zhao, H.; Lam, J. W. Y.; Tang, L.; Lu, P.;
Wang, C.; Liu, Y.; Wang, Z.; Zheng, Q.; Sun, J.; Ma, Y.; Tang, B., J.
Phys. Chem. C. 2010, 114, 6090–6099.
(5) Zhang, G.; Palmer, G. M.; Dewhirst, M. W.; Fraser, C. L., Nat.
Mater. 2009, 8, 747ꢀ751.
ACS Paragon Plus Environment

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Page 6 of 7
(35) Wei, J.; Liang, B.; Duan, R.; Cheng, Z.; Li, C.; Zhou, T.; Yi,
Y.; Wang, Y., Angew. Chem. Int. Ed. 2016, 55, 15589ꢀ15593.
(36) Hirata, S.; Totani, K.; Zhang, J.; Yamashita, T.; Kaji, H.;
Marder, S. R.; Watanabe, T.; Adachi, C., Adv. Funct. Mater. 2013,
23, 3386ꢀ3397
(37) Li, D.; Lu, F.; Wang, J.; Hu, W.; Cao, X. M.; Ma, X.; Tian, H.,
J. Am. Chem. Soc. 2018, 140, 1916ꢀ1923.
1
2
3
4
5
6
7
8
(38) AlꢀAttar, H. A.; Monkman, A. P., Adv. Funct. Mater. 2012, 22,
3824ꢀ3832.
(39) Chen, X.; Xu, C.; Wang, T.; Zhou, C.; Du, J.; Wang, Z.; Xu, H.;
Xie, T.; Bi, G.; Jiang, J., Zhang, X.; Dems, J.; Trindle, C.; Luo, Y.;
Zhang, G., Angew. Chem. Int. Ed. 2016, 55, 9872ꢀ9876.
(40) Yang, X.; Yan, D., Chem. Sci. 2016, 7, 4519ꢀ4526.
(41) Cheng, Z.; Shi, H.; Ma, H.; Bian, L.; Wu, Q.; Gu, L.; Cai, S.;
Wang, X.; Xiong, W.; An, Z.; Huang, W., Angew. Chem. Int. Ed.
2018, 57, 678ꢀ682.
(42) Cai, S.; Shi, H.; Zhang, Z.; Wang, X.; Ma, H.; Gan, N.; Wu, Q.;
Cheng, Z.; Ling, K.; Gu, M.; Ma, C.; Gu, L.; An, Z.; Huang, W.,
Angew. Chem. Int. Ed. 2018, 57, 4005ꢀ4009.
(43) Gong, Y.; Zhao, L.; Peng, Q.; Fan, D.; Yuan, W. Z.; Zhang, Y.;
Tang, B., Chem. Sci. 2015, 6, 4438ꢀ4444.
(44) Kuno, S.; Akeno, H.; Ohtani, H.; Yuasa, H., Phy. Chem. Chem.
Phy. 2015, 17, 15989ꢀ15995.
(45) Wang, L.; Zhang, J.; Kim, B.; Peng, J.; Berry, S. N.; Ni, Y.; Su,
D.; Lee, J.; Yuan, L.; Chang, Y. T., J. Am. Chem. Soc. 2016, 138,
10394ꢀ10397.
(46) Fermi, A.; Bergamini, G.; Roy, M.; Gingras, M.; Ceroni, P., J.
Am. Chem. Soc. 2014, 136, 6395ꢀ6400.
(47) Xiao, L.; Wu, Y.; Yu, Z.; Xu, Z.; Li, J.; Liu, Y.; Yao, J.; Fu, H.,
Chem. Eur. J. 2018, 24, 1801ꢀ1805.
(48) An, Z.; Zheng, C.; Tao, Y.; Chen, R.; Shi, H.; Chen, T.; Wang,
Z.; Li, H.; Deng, R.; Liu, X.; Huang, W., Nat. Mater. 2015, 14, 685ꢀ
690.
(49) Zhao, W.; He, Z.; Lam, J. W.; Peng, Q.; Ma, H.; Shuai, Z.; Bai,
G.; Hao, J.; Tang, B., Chem. 2016, 1, 592ꢀ602.
(50) Pedersen, C. J., J. Am. Chem. Soc. 1967, 89, 7017ꢀ7036.
(51) Chen, S.; Slattum, P.; Wang, C.; Zang, L., Chem. Rev. 2015,
115, 11967ꢀ11998.
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